Swellable packer with enhanced sealing capability

Abstract

A swellable packer with enhanced sealing capability. A packer assembly includes multiple seal elements, each seal element being swellable downhole, each seal element having at least one face inclined relative to a longitudinal axis of the assembly, and the inclined faces of adjacent seal elements contacting each other. A method of constructing a packer assembly having a desired differential pressure sealing capability includes: providing a base pipe and multiple seal elements, each seal element being swellable in a downhole environment, and each seal element having a predetermined differential pressure sealing capability less than the desired sealing capability; and after the desired sealing capability is determined, installing a selected number of the seal elements on the base pipe, so that the combined predetermined differential pressure sealing capabilities of the installed seal elements is at least as great as the desired sealing capability.

What is claimed is: 
     
       1. A packer assembly, comprising:
 multiple annular-shaped seal elements which swell and expand into contact with a well surface in response to contact with a fluid, each seal element having at least one face inclined relative to a longitudinal axis of the packer assembly, and the inclined faces of adjacent seal elements contacting each other, wherein at least one of the inclined faces radially outwardly biases at least one seal element into contact with the well surface when the multiple seal elements swell downhole. 
 
     
     
       2. The packer assembly of  claim 1 , wherein the multiple seal elements are installed on a single base pipe. 
     
     
       3. The packer assembly of  claim 2 , wherein the seal elements slide onto the base pipe from an end thereof. 
     
     
       4. The packer assembly of  claim 2 , wherein at least one of the seal elements has a longitudinal slit therein which permits installation on the base pipe in a direction lateral to the longitudinal axis. 
     
     
       5. The packer assembly of  claim 2 , wherein at least one of the seal elements is wrapped helically about the base pipe. 
     
     
       6. The packer assembly of  claim 1 , wherein at least two support rings straddle the multiple seal elements. 
     
     
       7. The packer assembly of  claim 6 , wherein the seal elements are radially extendable into sealing contact with a well surface without decreasing a longitudinal distance between the support rings. 
     
     
       8. The packer assembly of  claim 6 , wherein at least one of the support rings includes a face inclined relative to the longitudinal axis, and wherein the support ring face is arranged to bias an adjacent one of the seal elements into sealing contact when the adjacent seal element swells downhole. 
     
     
       9. The packer assembly of  claim 6 , wherein at least one of the support rings includes a surface which is radially offset relative to a surface of an adjacent one of the seal elements, and wherein the support ring surface is arranged to bias the adjacent seal element into sealing contact when the adjacent seal element swells downhole. 
     
     
       10. The packer assembly of  claim 9 , wherein the support ring surface is parallel to the adjacent seal element surface. 
     
     
       11. The packer assembly of  claim 1 , wherein the seal elements are radially extendable into sealing contact with a well surface without longitudinally compressing the seal elements. 
     
     
       12. The packer assembly of  claim 1 , wherein the seal elements include first seal elements straddling a second seal element, and wherein the second seal element is less rigid than the first seal elements. 
     
     
       13. The packer assembly of  claim 12 , wherein at least one of the first seal elements includes a reinforcement material in a seal material. 
     
     
       14. The packer assembly of  claim 13 , wherein the seal material is a swellable seal material. 
     
     
       15. The packer assembly of  claim 1 , wherein the seal elements have corresponding varied levels of rigidity in a direction parallel to the longitudinal axis.